Radio receiving system



imatenteoi ingo 2@ cirrrreomnr o1 f WALTER BULLQCE, QF NEW A"Zt'it N.Y., .LSSEGNJ @LF FORTI-NEWT; @EUR @MT T@ FREDERIC E13/OUTER, @E NEWEURE, N.

Application nica eanuary 23, 195533. Serial @iL-lite?,

To aZZ wwm it may concern:

Be it known that i, `Wsrrnn i-. Bonnoon, A

a citizen ci the United States, residing at New Yori: city, in thecounty or" Kings and State of New York, have invented certain new andnseiui improvements in Radio Receiving Systems, iuiiy described andrepresented in the oiiowing speciiication and the accompanying drawings,forming a part of the saineq This invention reiates to radio receivingsystems.7

@biects ci the invention' are z-To provide receiving system having asingie energy absorbing circuit combined with a :Aoiuraiity of detectingcircuits, each of which may be tuned for the reception of messages ofany desired 'wave iength Without aecting the tuning of the others;permit a sharper tuning o'f ieceiving circuits than-Was hereto- 'forepossibie; to avoid the necessity oit retuning in case oaf a change inthe characteristics of the energy absorbing circuit; and to preventradiation o* energy 'from the energy absorbing circuit of the system.

iin radio receiving systems heretofore used, has been customary to use,as part oi the system, energy absorbing circuit having a period ofosciiiation corresponding. to 'the Wave iength oi the message to bereceived, men the energy absorbing circuit ci such a system is tuned toosciiiate ier a particular wave iength, it is impracticabie to use thesystem to receive at the same tirne messages in other Wave lengths. Forthis reason it has been customary vto use separate receiving systems,each havin its own energy absorbing circuit, in or er to pro- `vide iorsimuitaneous reception ci messages ci ditierent Wave iengths, butwhere,as on board vessels, itfhas been necessary to piace the antenne ot thevarious receiving systems close to one another, the inductance iiniragebetween the antenn has rendered it ditiicuit to tune each receivingsystem independentiy of the othere The sharpness ci" tuning possible inordinary receiving systems, and particuiariy those in "which an antennais used, has been limited by the damping `factor of the energy absorbingcircuitv resuiting both from the ohrnic resistance in the connectionbetween the antenna and the ground and from the rie-radiation et energyfrom the circuit. Furthermore,- in euch systems dicuity has piene, andaise in ali cases Where the antenna and its mounting are subjected tosevere Wind pressure.

in accordance with rey invention, these other disadvantages ci thereceiving systems heretofore used are eiirninated by the use of energyabsorbing circuit which is made apericdic, so that the energy absorbedby the circuit from radiations f ii different Wave iengths producesJini-creo ug troni 4swinging or other s tionai current irnilouisesfinthe circuit, cut

no oscillatory currentsc "fiiitii such aperiodic energy absorbingcircuit, use one or more independent osciiiatory circuits which areassociated with theenergy absorbing circuit in such manner thatvariations et notenin the energy absorbing circuit are inipressed,either directiy' or indirectiy, upon each of the osciiiatory circuits.Each of the oscillatory circuits may be tuned so that its natural periodor osciiiaticn corresponds to the Wave iength of a dierent message berece1ved. detector ci? any ordinary type is connected across eachcsciiiatory circuit., iin

the operation of my receiving system, therefore, radiations of aiiditerent Wave ien the produce current impuises in the energy absorbingcircuit, whiie csciilating currents corresponding to radiations ordifferent' Wave lengths may be produced separateiy in the various tunedcircuits associated with the energy absorbing circuit.,

' 'in order that the invention may cieariy be understood, will describein detaii certain sneciiic embodiments oitJ it., it shaii, for the` sakeof iiiustration, describe a receiving sys-l tern in which the energyabsorbing circuit contains an antenna or aerial. itt shouid beunderstood, however, that the invention may be carried out also by theuse of other energy absorbing circuits, such as ioop circuits, or

circuits connected to two different pointe of the ground,

A grounded antenna forms an energy ab eorbing circuit havlng a natur-aiperiodi or? are impressed upon an oscillatory circuit,

either directly, by connecting the oscillatory circuit in the energyabsorbinocircuit or linking it to the energy absorbing circuit throughmutual inductance, or indirectly, through the medium of a repeater. yInthe latter case, a three-element electron emission diant electricenergy.l

vacuum tube may be used as the repeater by which potential lvariationsin the energy absorbing circuit are indirectly impressed upon theoscillatory circuit, and this tube may serve also as the rectifier inthe energy absorbing circuit.

In the drawings, Figure 1 illustrates diagrammatically an aperiodicenergy absorbing circuit embodying the invention,

Fig. 2 illustrates la modification containing the type of rectifierwhich I have found best in practice,

Fig. .3 illustrates two ways in which potential differences in anaperiodic energy absorbing circuit may be' impressed upon oscillatorycircuits and Fig. 4 shows ya modification including three oscillatorycircuits on which potential variations in the -energy absorbing circuitare impressed indirectly thru the medium of vacuum tube repeaters.

In Fig. 1, I have illustrated diagrammatically an .aperiodic energy.absorbing circuit embodying the invention. This circuit l'consists ofan antenna E connected to the ground through a suitable rectifierindicated diagrammatically at R and servingto permit current to flowfrom the antenna to the ground, while preventing current Ifrom` vflowingfrom the ground to the antenna.

While the invention is not limited to the use of any particular type ofrectifier to render the energy absorbing circuit aperiodic, therectifier used must be capable of operating with the minute voltages andcurrents produced in a circuit Aabsorbing ra- In Fig. 2 is illustratedan aperiodic energy absorbing circuit containing the typeof rectifierwhich I have found best in practice.' The rectifier R consists of athreeelement electron' emission vacuum tube V having a cathode Fy heatedby a battery A forV the emission of electrons, a plate P main- Atainedat a potential higher than that of the cathode by a battery B, and algrid element G located between the cathode and the plate. The antenna Eis connected to the grid element G, while the cathode element F isconnected tothe ground. The. electrons emitted from the cathode F flowto the plate P, and to the grid element G when the potential of the gridis higher than that of the cathode. Electrons cannot, however, flow fromthe Vgrid to the cathode. Consequently, when differences of potentialbetween the antenna E and the ground are created by radio frequency pathfrom the antenna to' the ground and, therefore, does not permit currentoscillations of radio frequency between tlie antenna and thel ground.Thus, notwithstanding the leakage path-X which bridges the rectifier,the energy absorbing circuit is aperiodic, that is, it has not a naturalperiod of oscillation within the range of radio frequencies.

Fig. 3 illustrates two ways in which potential differences in anaperiodic energy absorbing circuitmay be impressed upon oscillatorycircuits. The antenna E is. connected to thel ground by a connector 10having two branches 111, 112. The branch 11l contains a suitablerectifier R1, while the branch 1i2 contains a similar rectifier R2.Anoscillatorycircuit O1 is connected in the branch 111 betweentherectifier R1 and the ground. The oscillatory circuit contains aninductance L,l and a variable condenser C1 connected together to form aclosed circuit which may be tuned so that an oscillatory current will beset up in it by any series of potential variations in the energyabsorbing circuit in which it is connected. A detector I)l is connectedacross the oscillatory circuit 0, to rectify the radio frequencyoscillations in the circuit and produce audible signals in the usualmanner.

The branch 112 contains an inductance T between the rectifier R2 and theground. This inductance is linked with an inductance T in a closedcircuit S containing an oscillatory circuit O2 similar to the circuitO1. This circuit may be tuned to respond to a different series ofpotential differences in the energy vabsorbing circuit which areimlpressed on it by the inductance linkage be- Oscilla? tween theinductances T and T. tions in this circuit are detected by a detector D2connected across it.

It should be noted that the rectifiers R1', 1

R2, besides rendering the energy absorbing' Leccese circuit aperiodic,serve to prevent any flow of current between the twov tuned circuits 01,02, and thus permit the tuning of these circuits independently of eachother., lt

should be understood that the circuits O1,

O2, are to be placed, farenough apart, so

that there is no mutual inductance between them. f

' In Fig. 4 is shown an aperiodic energy l0 absorbing circuit combinedwith three oscillatory circuits on which potential variations in theenergy absorbing circuit are .im-

pressed indirectly through the medium' of' vacuum tube repeaters. Thesystem examplified in Fig. 4 is, according to my present knowledge, thebest embodiment of my invention.

In Fig. 4, the Aantenna E is connected, by a conductor 10', having threebranches 11,

11b, 11, to the grids Gb, Gb, Gb, of three 4three-element electronemission vacuum tubes Vb, Vb, Vb. The filaments Fb, Fb, F of the threetubes are grounded by means of conductors 12b, 12b, 12. A leakage path-X of high resistance, for example, one megaohm, is connected betweenone of the branches of the conductor 10 and one of the` oundedconductors. The tubes Vb, Vb,

heating batteries Ab, Ab, A, and the usual anode potential batteries B,Bb, Bb.

A closed oscillatory circuit 0b containing an inductance Lla and 'acondenser C8, one or both of which are variable soas to pe i t tuning ofthe circuit '05, is connected between the plate element Pb and thefilament element Fb of the tube Vb. lin the form shown, the oscillatocircuit is connected in series with the ano e potential battery Bb,

40 but this is not essential.

Across the oscillatory circuit 0b is connected a detector or detectingsystem Db which is illustrated as including a condenser 15b, athree-element vacuum tube lob, a

grid resistance 17, .a cathode heating battery l8b, an anode potentialbattery and a telephone 20, all connected in the usual manner.

An oscillatory circuit Obl containing an in ductance Lb and a condenserCb, one or both of which are variable, is connected between the filamentFb 'and the plate Pb of the tube Vb. A detecting system lDb is connectedacross the oscillatory circuit b. The de- 55 tecting s stein Db issimilar to the detecting system b, except that the connections are suchthata art of the anode potential battery Bb of tlie tube Vb is used asthe anode potential battery 19b of the detector tube lob..

An oscillatory circuit 0 containing an inductance Lc and a condenser @0,one or both of which are variable, is connected between the filament lF"and the plate Pb of the tube V. The detecting system 'Db which isconnected across the oscillatory circuit @b c are provided with theusual cathode is similar tothe detecting systemDb, except that the platecircuit of the detector tube y 16c is made regenerative by the inclusionof an inductance 21 which is in mutualinductive relation with theinductance Lc of the "rent inthe energy absorbing circuit in onedirection only, tha-t is, from the antenna to the ground.

Potential ing circuit are impressed on the grids Gb, Gb, Gb of the tubesVb, Vb, Vb, so that potential variations which are similar to, and ofthe same frequency as, those in the energy absorbing circuit are createdin the platefilament circuit of each tube. variationsA in these circuitsare im ressed upon the oscillatory circuits 0b, b, Ob. rlihese threevacuum tubes, therefore, serve as repeaters `for indirectly impressingpotential variations in the energy absorbing circuit upon the threeoscillatory circuits. `The vacuum tubes Vb, Vb, Vb serveJ also toisolate the three oscillatory circuits from each other so as to preventany flow of current from one of t lt should be understood 'thatthe-oscillatory circuits are -located far enough apart to eliminateinductive linka e between them.

As a result, each oscil atory circuit may be tuned independently of theother oscillatory circuits, and independently 'of the' characteristicsof the antenna circuit. By tuning the three oscillatory circuits so thatthey will respond to impulses of dili'erent frequency, three sets ofsignals of diderent wave lengths may be received simultaneously, one ineach ot the detectors, although the radiant energy of all three sets ofsignals is absorbed in a single antenna circuit. Furthermore, the tuningof any oneof the oscillatory circuits may be changed without in any wayadectingthe tuning of the other oscillatory circuits. From-theillustrative examples which have been described, it will readily beunderstood that the invention may be carried out so as to associate lany'desired number ot independent oscillatory circuits with a singleaperiodic energy absorbing circuit, and that any desired type oidetector or detecting.

and amplifying system may be used in con nection with each of theoscillatory circuits.

What is claimed is:

1. A radio receiving system, comprising an energy absorbing circuit, aplurality ci? three-element electron emission vacuum tubes having theirgrid and lament elles ments connected in parallel in said circuit. f

variations in the energy absorbi ese circuits to another.`

The potential iis so as to prevent a ffiow of current in one -directiontherein, a leakage path between one connected betweenthe plate and thefilament elements of each of said tubes, separate means for varying thenatural period of each of said oscillatory circuits, and a detectorassociated with each oscillatory circuit.

`2. A radio receivin system, comprising lan antenna, a connectionbetween said antenna and the ground having a plurality of parallelbranches, an oscillatory circuit associated with each of said branchesin such manner that potential variations in the energy absorbing circuit.are impressed upon it, a rectifier in each branch of said connection,said rectiers bein arranged to prevent a flow of current 1n onedirection in the energy absorbin circuit and to'prevent a iow of current.etween the oscillatory circuits, -separate means for varying thenatural period of each or the oscillatory cirarcanes cuits, and adetector associated with each oscillatory circuit. y

3. A radio receiving system, comprising an antenna, a plurality ofthree-element eiectron emission vacuum tubes, a connection between theantenna and the grid elenient of each of said tubes, a connectionbetween the lament element of'each tube and the ground, a leakage pathbetween the grid and lilament elements of one of said tubes to preventthe grids from acquiring a static negative charge and having aresistance too highrto permit radio frequency current 0S-v cillations,said tubes andsaid leakage path forming the only conductive path betweenthe antenna and the ground and forming with the antenna an aperiodicenergy absorbing circuit, a plurality of oscillatory circuits, oneconnected between the plate element and the filament element of each ofsaid tubes, separate means for varying the natural period of each of theoscillatory circuits, and a detector associated with each oscillatory`circuit.

` In testimony whereof have hereunto set i my hand.

'WALTER H. BULLGCK.

